<?php

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/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 5.1.6 or newer
 *
 * @package		CodeIgniter
 * @author		ExpressionEngine Dev Team
 * @copyright	Copyright (c) 2008 - 2011, EllisLab, Inc.
 * @license		http://codeigniter.com/user_guide/license.html
 * @link		http://codeigniter.com
 * @since		Version 1.0
 * @filesource
 */

// ------------------------------------------------------------------------


/**
 * Typography Class
 *
 *
 * @access		private
 * @category	Helpers
 * @author		ExpressionEngine Dev Team
 * @link		http://codeigniter.com/user_guide/helpers/
 */
class CI_Typography {
	
	// Block level elements that should not be wrapped inside <p> tags
	var $block_elements = 'address|blockquote|div|dl|fieldset|form|h\d|hr|noscript|object|ol|p|pre|script|table|ul';
	
	// Elements that should not have <p> and <br /> tags within them.
	var $skip_elements = 'p|pre|ol|ul|dl|object|table|h\d';
	
	// Tags we want the parser to completely ignore when splitting the string.
	var $inline_elements = 'a|abbr|acronym|b|bdo|big|br|button|cite|code|del|dfn|em|i|img|ins|input|label|map|kbd|q|samp|select|small|span|strong|sub|sup|textarea|tt|var';
	
	// array of block level elements that require inner content to be within another block level element
	var $inner_block_required = array ('blockquote' );
	
	// the last block element parsed
	var $last_block_element = '';
	
	// whether or not to protect quotes within { curly braces }
	var $protect_braced_quotes = FALSE;
	
	/**
	 * Auto Typography
	 *
	 * This function converts text, making it typographically correct:
	 * - Converts double spaces into paragraphs.
	 * - Converts single line breaks into <br /> tags
	 * - Converts single and double quotes into correctly facing curly quote entities.
	 * - Converts three dots into ellipsis.
	 * - Converts double dashes into em-dashes.
	 * - Converts two spaces into entities
	 *
	 * @access	public
	 * @param	string
	 * @param	bool	whether to reduce more then two consecutive newlines to two
	 * @return	string
	 */
	function auto_typography($str, $reduce_linebreaks = FALSE) {
		if ($str == '') {
			return '';
		}
		
		// Standardize Newlines to make matching easier
		if (strpos ( $str, "\r" ) !== FALSE) {
			$str = str_replace ( array ("\r\n", "\r" ), "\n", $str );
		}
		
		// Reduce line breaks.  If there are more than two consecutive linebreaks
		// we'll compress them down to a maximum of two since there's no benefit to more.
		if ($reduce_linebreaks === TRUE) {
			$str = preg_replace ( "/\n\n+/", "\n\n", $str );
		}
		
		// HTML comment tags don't conform to patterns of normal tags, so pull them out separately, only if needed
		$html_comments = array ();
		if (strpos ( $str, '<!--' ) !== FALSE) {
			if (preg_match_all ( "#(<!\-\-.*?\-\->)#s", $str, $matches )) {
				for($i = 0, $total = count ( $matches [0] ); $i < $total; $i ++) {
					$html_comments [] = $matches [0] [$i];
					$str = str_replace ( $matches [0] [$i], '{@HC' . $i . '}', $str );
				}
			}
		}
		
		// match and yank <pre> tags if they exist.  It's cheaper to do this separately since most content will
		// not contain <pre> tags, and it keeps the PCRE patterns below simpler and faster
		if (strpos ( $str, '<pre' ) !== FALSE) {
			$str = preg_replace_callback ( "#<pre.*?>.*?</pre>#si", array ($this, '_protect_characters' ), $str );
		}
		
		// Convert quotes within tags to temporary markers.
		$str = preg_replace_callback ( "#<.+?>#si", array ($this, '_protect_characters' ), $str );
		
		// Do the same with braces if necessary
		if ($this->protect_braced_quotes === TRUE) {
			$str = preg_replace_callback ( "#\{.+?\}#si", array ($this, '_protect_characters' ), $str );
		}
		
		// Convert "ignore" tags to temporary marker.  The parser splits out the string at every tag
		// it encounters.  Certain inline tags, like image tags, links, span tags, etc. will be
		// adversely affected if they are split out so we'll convert the opening bracket < temporarily to: {@TAG}
		$str = preg_replace ( "#<(/*)(" . $this->inline_elements . ")([ >])#i", "{@TAG}\\1\\2\\3", $str );
		
		// Split the string at every tag.  This expression creates an array with this prototype:
		//
		//	[array]
		//	{
		//		[0] = <opening tag>
		//		[1] = Content...
		//		[2] = <closing tag>
		//		Etc...
		//	}
		$chunks = preg_split ( '/(<(?:[^<>]+(?:"[^"]*"|\'[^\']*\')?)+>)/', $str, - 1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY );
		
		// Build our finalized string.  We cycle through the array, skipping tags, and processing the contained text
		$str = '';
		$process = TRUE;
		$paragraph = FALSE;
		$current_chunk = 0;
		$total_chunks = count ( $chunks );
		
		foreach ( $chunks as $chunk ) {
			$current_chunk ++;
			
			// Are we dealing with a tag? If so, we'll skip the processing for this cycle.
			// Well also set the "process" flag which allows us to skip <pre> tags and a few other things.
			if (preg_match ( "#<(/*)(" . $this->block_elements . ").*?>#", $chunk, $match )) {
				if (preg_match ( "#" . $this->skip_elements . "#", $match [2] )) {
					$process = ($match [1] == '/') ? TRUE : FALSE;
				}
				
				if ($match [1] == '') {
					$this->last_block_element = $match [2];
				}
				
				$str .= $chunk;
				continue;
			}
			
			if ($process == FALSE) {
				$str .= $chunk;
				continue;
			}
			
			//  Force a newline to make sure end tags get processed by _format_newlines()
			if ($current_chunk == $total_chunks) {
				$chunk .= "\n";
			}
			
			//  Convert Newlines into <p> and <br /> tags
			$str .= $this->_format_newlines ( $chunk );
		}
		
		// No opening block level tag?  Add it if needed.
		if (! preg_match ( "/^\s*<(?:" . $this->block_elements . ")/i", $str )) {
			$str = preg_replace ( "/^(.*?)<(" . $this->block_elements . ")/i", '<p>$1</p><$2', $str );
		}
		
		// Convert quotes, elipsis, em-dashes, non-breaking spaces, and ampersands
		$str = $this->format_characters ( $str );
		
		// restore HTML comments
		for($i = 0, $total = count ( $html_comments ); $i < $total; $i ++) {
			// remove surrounding paragraph tags, but only if there's an opening paragraph tag
			// otherwise HTML comments at the ends of paragraphs will have the closing tag removed
			// if '<p>{@HC1}' then replace <p>{@HC1}</p> with the comment, else replace only {@HC1} with the comment
			$str = preg_replace ( '#(?(?=<p>\{@HC' . $i . '\})<p>\{@HC' . $i . '\}(\s*</p>)|\{@HC' . $i . '\})#s', $html_comments [$i], $str );
		}
		
		// Final clean up
		$table = array (

		// If the user submitted their own paragraph tags within the text
		// we will retain them instead of using our tags.
		'/(<p[^>*?]>)<p>/' => '$1', // <?php BBEdit syntax coloring bug fix


		// Reduce multiple instances of opening/closing paragraph tags to a single one
		'#(</p>)+#' => '</p>', '/(<p>\W*<p>)+/' => '<p>', 

		// Clean up stray paragraph tags that appear before block level elements
		'#<p></p><(' . $this->block_elements . ')#' => '<$1', 

		// Clean up stray non-breaking spaces preceeding block elements
		'#(&nbsp;\s*)+<(' . $this->block_elements . ')#' => '  <$2', 

		// Replace the temporary markers we added earlier
		'/\{@TAG\}/' => '<', '/\{@DQ\}/' => '"', '/\{@SQ\}/' => "'", '/\{@DD\}/' => '--', '/\{@NBS\}/' => '  ', 

		// An unintended consequence of the _format_newlines function is that
		// some of the newlines get truncated, resulting in <p> tags
		// starting immediately after <block> tags on the same line.
		// This forces a newline after such occurrences, which looks much nicer.
		"/><p>\n/" => ">\n<p>", 

		// Similarly, there might be cases where a closing </block> will follow
		// a closing </p> tag, so we'll correct it by adding a newline in between
		"#</p></#" => "</p>\n</" );
		
		// Do we need to reduce empty lines?
		if ($reduce_linebreaks === TRUE) {
			$table ['#<p>\n*</p>#'] = '';
		} else {
			// If we have empty paragraph tags we add a non-breaking space
			// otherwise most browsers won't treat them as true paragraphs
			$table ['#<p></p>#'] = '<p>&nbsp;</p>';
		}
		
		return preg_replace ( array_keys ( $table ), $table, $str );
	
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Format Characters
	 *
	 * This function mainly converts double and single quotes
	 * to curly entities, but it also converts em-dashes,
	 * double spaces, and ampersands
	 *
	 * @access	public
	 * @param	string
	 * @return	string
	 */
	function format_characters($str) {
		static $table;
		
		if (! isset ( $table )) {
			$table = array (// nested smart quotes, opening and closing
			// note that rules for grammar (English) allow only for two levels deep
			// and that single quotes are _supposed_ to always be on the outside
			// but we'll accommodate both
			// Note that in all cases, whitespace is the primary determining factor
			// on which direction to curl, with non-word characters like punctuation
			// being a secondary factor only after whitespace is addressed.
			'/\'"(\s|$)/' => '&#8217;&#8221;$1', '/(^|\s|<p>)\'"/' => '$1&#8216;&#8220;', '/\'"(\W)/' => '&#8217;&#8221;$1', '/(\W)\'"/' => '$1&#8216;&#8220;', '/"\'(\s|$)/' => '&#8221;&#8217;$1', '/(^|\s|<p>)"\'/' => '$1&#8220;&#8216;', '/"\'(\W)/' => '&#8221;&#8217;$1', '/(\W)"\'/' => '$1&#8220;&#8216;', 

			// single quote smart quotes
			'/\'(\s|$)/' => '&#8217;$1', '/(^|\s|<p>)\'/' => '$1&#8216;', '/\'(\W)/' => '&#8217;$1', '/(\W)\'/' => '$1&#8216;', 

			// double quote smart quotes
			'/"(\s|$)/' => '&#8221;$1', '/(^|\s|<p>)"/' => '$1&#8220;', '/"(\W)/' => '&#8221;$1', '/(\W)"/' => '$1&#8220;', 

			// apostrophes
			"/(\w)'(\w)/" => '$1&#8217;$2', 

			// Em dash and ellipses dots
			'/\s?\-\-\s?/' => '&#8212;', '/(\w)\.{3}/' => '$1&#8230;', 

			// double space after sentences
			'/(\W)  /' => '$1&nbsp; ', 

			// ampersands, if not a character entity
			'/&(?!#?[a-zA-Z0-9]{2,};)/' => '&amp;' );
		}
		
		return preg_replace ( array_keys ( $table ), $table, $str );
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Format Newlines
	 *
	 * Converts newline characters into either <p> tags or <br />
	 *
	 * @access	public
	 * @param	string
	 * @return	string
	 */
	function _format_newlines($str) {
		if ($str == '') {
			return $str;
		}
		
		if (strpos ( $str, "\n" ) === FALSE && ! in_array ( $this->last_block_element, $this->inner_block_required )) {
			return $str;
		}
		
		// Convert two consecutive newlines to paragraphs
		$str = str_replace ( "\n\n", "</p>\n\n<p>", $str );
		
		// Convert single spaces to <br /> tags
		$str = preg_replace ( "/([^\n])(\n)([^\n])/", "\\1<br />\\2\\3", $str );
		
		// Wrap the whole enchilada in enclosing paragraphs
		if ($str != "\n") {
			// We trim off the right-side new line so that the closing </p> tag
			// will be positioned immediately following the string, matching
			// the behavior of the opening <p> tag
			$str = '<p>' . rtrim ( $str ) . '</p>';
		}
		
		// Remove empty paragraphs if they are on the first line, as this
		// is a potential unintended consequence of the previous code
		$str = preg_replace ( "/<p><\/p>(.*)/", "\\1", $str, 1 );
		
		return $str;
	}
	
	// ------------------------------------------------------------------------
	

	/**
	 * Protect Characters
	 *
	 * Protects special characters from being formatted later
	 * We don't want quotes converted within tags so we'll temporarily convert them to {@DQ} and {@SQ}
	 * and we don't want double dashes converted to emdash entities, so they are marked with {@DD}
	 * likewise double spaces are converted to {@NBS} to prevent entity conversion
	 *
	 * @access	public
	 * @param	array
	 * @return	string
	 */
	function _protect_characters($match) {
		return str_replace ( array ("'", '"', '--', '  ' ), array ('{@SQ}', '{@DQ}', '{@DD}', '{@NBS}' ), $match [0] );
	}
	
	// --------------------------------------------------------------------
	

	/**
	 * Convert newlines to HTML line breaks except within PRE tags
	 *
	 * @access	public
	 * @param	string
	 * @return	string
	 */
	function nl2br_except_pre($str) {
		$ex = explode ( "pre>", $str );
		$ct = count ( $ex );
		
		$newstr = "";
		for($i = 0; $i < $ct; $i ++) {
			if (($i % 2) == 0) {
				$newstr .= nl2br ( $ex [$i] );
			} else {
				$newstr .= $ex [$i];
			}
			
			if ($ct - 1 != $i)
				$newstr .= "pre>";
		}
		
		return $newstr;
	}

}
// END Typography Class

/* End of file Typography.php */
/* Location: ./system/libraries/Typography.php */